The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 10, 2004
Filed:
May. 30, 2002
Ruairi Seosamh O'Meadhra, Kingsport, TN (US);
Robert Lin, Kingsport, TN (US);
Shane Kipley Kirk, Church Hill, TN (US);
Brian David McMurray, Bristol, VA (US);
Eastman Chemical Company, Kingsport, TN (US);
Abstract
Disclosed is a method for the recovery of crystalline terephthalic acid containing less than about 150 ppmw p-toluic acid by subjecting a solution of terephthalic acid containing minor amounts of p-toluic acid to crystallization in a crystallization zone comprising a plurality of series-connected crystallizers wherein the solution is subjected to rate-controlled evaporative cooling by sequential reduction in pressure and temperature to cause crystallization of terephthalic acid, wherein the pressure of the solution at the end of the crystallization zone is about ambient pressure or less. Solvent which is evaporated from the crystallizers is collected and condensed and the condensed solvent is returned to the crystallization zone at a point subsequent to the crystallizer from which it was obtained.